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1.
to take with out asking permission.
Are you a winner or a loser? If you are a winner you will go ahead and Uncle Jack that last piece of chicken.
by shabagames October 13, 2006
 
2.
Another name for Jack Daniels. Also used as a family member to a drunk.
"Goddammned, Uncle Jack Really Obliterated My Ass Last Night!"

"Jason and I Drank A Whole handle of Good Ole' Uncle Jack Last Night!"
by Neely December 13, 2004
 
3.
Accent with heavy emphasis on phlegm.

Almost sounds like there is a Y in front of every vowel and sounds very similar to Hebrew.
Cousin Shane: Uncle Jack! Wherye's Yeall Thye Pyunch!!!

Uncle Jack: LOAH!!!! PYUNCH!!!!
by RamboLurch December 10, 2009
 
4.
Your somewhat deranged crazy zoo worker uncle. Apparently the water there has made him crazy, because he now goes around collecting elephant sperm…and helping people off the elephants. He also consistently needs helpers for his collection program. He is a sad, sad person to have in your family.
If your uncle Jack helps you off an elephant, would you help your uncle Jack off an elephant
by Cousin Fred2 August 18, 2013
 
5.
The most amazing dumpster diver/ garbage picker/ garbage sorter/ trash hoarder in the world. He dwells in he Big Blue Box in Thunder Bay. Uncle Jack enjoys spending time with his family (Jacob Hoggard, Dave Rosin, Chris Crippin, Tommy Mac) and taking long, romantic strolls through the landfill at sunset.
Uncle Jack, what are you looking for in the big blue box?
by Uncle Jack February 28, 2012
 
6.
A term used by Jews to insult fellow Jews who happen to be members of the Republican Party, or simply have more conservative views.
The Republican Jewish Coaltion are a bunch of Uncle Jacks!
by Theo L. January 02, 2006
 
7.
To find a small creature and to put it in any hole you have, while singing Stronger by Britney spears
Nick found a bullfrog and proceded to Uncle Jack with it
by Mikey December 01, 2004